Kinematic Chain

Normal kinematics of the neck: The interplay between the cervical and thoracic spines

By Sharon Tsang, Grace Szeto, Raymond Lee. Published in Manual Therapy 2013 Oct;18(5):431-7.

The movement coordination between the cervical and thoracic spine was examined in 34 asymptomatic participants (24 female and 10 male). The authors used 3D motion sensors attached to the skin overlying the head, T1, T6, and T12 spinous processes to measure the angular displacement of the cervical, upper thoracic, and lower thoracic spine during active neck movements. The study found that both the cervical and thoracic spines contribute to active neck motion, the greatest contribution being from the cervical region in all movement directions. The inter-regional movement coordination between the cervical spine and upper thoracic spine in all three planes of movement was found to be high.

Comments by Til Luchau on the paper by Tsang et al. (2013)

It takes a lot of careful work to measure big-picture correlations by piecing together the small-picture details, and this study has endeavoured to do just that. Even though, as Einstein said, “Not everything that counts can be counted, and not everything that can  be counted counts,” there is an odd kind of satisfaction when we get a quantified validation of something we knew already. Did you know that the spine moves when the neck does? Of course you did, but to see it laid out in nice charts done under carefully standardized experimental conditions reassures us that we really do know what we know. There are a few gems here, for instance, that the lumbars respond more to cervical side bending than to other neck movements. And it would be interesting to see if symptoms correlated to variations in the neck/spine movement coupling, rather than focus solely on asymptotic examples as this study did. Still, kudos to the authors for their diligent work.

Comments by Jo Key

A paper by Tsang et al. (2013) offers great kinematic data on functional movement of the upper spine and confirms the clinical approach of many experienced therapists successful in the treatment of ‘neck pain’.  The authors concluded that “the motion of the thoracic spine, in particular the upper thoracic spine, contributes to neck mobility, and that the upper thoracic spine should be included during clinical examination of neck dysfunction.”

I never treat the neck without addressing the thoracic spine Why so? No part of the body functions in isolation.  As the pelvis is to the lumbar spine, the upper thorax similarly acts as an adaptable platform of support for the head and neck. When our postural alignment changes, the natural movement kinematics of the whole spine and in particular those in the upper spine change. This further creates altered loading patterns (tension and compression) of the joints and soft tissues. In time, stiffness and pain will predictably ensue. This pretty much underlies all neck pain syndromes.

Many of us adopt a habitual slumped posture sitting at work and during many leisure activities – most of which also invariably involve use of the arms down in front of the body. The shoulder girdle and head and neck ‘hang forward’ off the thorax. We start to lose the sense of and ability to come back up to ‘neutral’. And in time the cervico-thoracic spine and upper thorax becomes stiff. The cervical joints above become the ‘victim’ and can’t assume a neutral position or move properly. Many ‘exercises’ prescribed for neck pain simply bother it more. The secret is to address the ‘criminal’ – to get mobility into the upper thorax and through the cervico-thoracic junction. To this end ‘The Fundamental Shoulder Patterns’ are a good start. (See:  www.keyapproach.com.au/blog ).

It’s important to realise that it isn’t simply a ‘stiff thorax’ which biomechanically effects cervical function. Changed posture-movement of the thorax also directly affects the kinematic patterns and loading patterns of the shoulder girdle. Appropriately treat the thorax and you’ll also make better gains with your shoulder patients

Secondly, thoracic joint dysfunction per se has a marked influence not only on the adjacent soft tissues but also upon autonomic function – the autonomic supply to the head and neck is T1-5 and that to the upper limb T2-10. The literature is increasingly showing sympathetic involvement in many central and peripheral pain syndromes.

Thirdly, the changed myo-mechanics and altered loading patterns also affect the fascial system which functionally connects the thorax to the head neck and upper limb. This tissue is richly innervated and forms a continuous whole body signalling system and structural web arranged in various layers.
If you are not addressing the thorax you will achieve limited results in the treatment of not only head and neck pain, but also shoulder and upper limb pain syndromes – not to mention low back and pelvic pain.